FILE PHOTO: A logo of Royal Dutch Shell is seen at Gastech, the world's biggest expo for the gas industry, in Chiba, Japan, April 4, 2017. REUTERS/Toru Hanai/File Photo

The fire broke out on the 45,000 bpd HCU, call the H-Oil Unit, at about 1:30 a.m. (0630 GMT) on Sunday, the sources said.

A Shell spokesman was not immediately available to comment.

No injuries were reported due to the blaze, the sources said.

The H-Oil Unit is a unique hydrocracker because it converts residual crude oil into motor fuels, especially diesel. Residual crude is normally processed by coking units. Hydrocrackers use hydrogen and a catalyst under high heat and pressure to produce motor fuels.